JP7510886B2 - Electronic clock and communication method - Google Patents

Description

The present invention relates to an electronic watch and a communication method.

In the past, a technology has been known for electronic watches equipped with solar cells that, when the solar cell detects an optical signal from a control terminal such as a mobile phone, executes control operations such as setting the time or setting an alarm depending on the content of the optical signal. In such electronic watches, if a detection circuit for detecting the optical signal is constantly running, power consumption increases and the continuous operation time of the electronic watch becomes shorter. Therefore, the detection circuit is activated when the user performs an operation on the electronic watch such as pressing a button.

In the electronic watch described above, when transmitting an optical signal to cause the electronic watch to perform a control operation, the user must operate both the control terminal and the electronic watch, which is cumbersome. Patent Document 1 describes an electronic watch that operates a detection circuit at a low communication rate, and when the detection circuit detects a synchronization signal at the low communication rate, switches the detection circuit to a high communication rate to receive a data signal. The electronic watch described in Patent Document 1 makes it possible to reduce power consumption associated with driving the detection circuit, without the user having to operate the electronic watch.

Japanese Patent No. 6482464

The above-mentioned synchronization signal is a time-varying change in the intensity of light according to a predetermined pattern. In order to reduce the power consumption of the detection circuit, it is preferable to lower the communication rate of the synchronization signal. However, if the communication rate is lowered, there is a risk that changes in the amount of received light that occur during daily use of the electronic watch, such as when the user of the electronic watch moves from the shade to the sun, will be erroneously detected as a synchronization signal. In this case, the detection circuit will frequently switch to a high communication rate, which will actually increase power consumption. Therefore, there has been a demand for reducing power consumption in such electronic watches.

The present invention has been made to solve the above-mentioned problems, and aims to provide an electronic watch and communication method that reduces the operational burden on the user for detecting optical signals while suppressing power consumption.

The electronic watch according to the present invention is an electronic watch that performs optical communication with a control terminal, and is characterized by having a photoelectric conversion unit that receives an optical signal from the control terminal and converts it into an electrical signal, a synchronization signal detection unit that receives a synchronization signal according to a first communication method transmitted from the control terminal via the photoelectric conversion unit, a transition signal detection unit that receives a transition signal according to a second communication method transmitted from the control terminal via the photoelectric conversion unit when the synchronization signal is detected, a control signal detection unit that receives a control signal according to a third communication method transmitted from the control terminal via the photoelectric conversion unit when the transition signal is detected, and a control unit that controls the electronic watch based on the control signal when the control signal is detected.

In addition, it is preferable that the electronic watch according to the present invention further includes a switching unit which switches the supply destination of the converted electrical signal from the synchronization signal detection unit to the transition signal detection unit when a synchronization signal is detected, and which switches the supply destination from the transition signal detection unit to the control signal detection unit when a transition signal is detected.

In addition, in the electronic watch according to the present invention, it is preferable that the switching unit switches the supply destination to the synchronization signal detection unit if a transition signal is not detected within a first time period after the supply destination is switched to the transition signal detection unit.

In addition, in the electronic watch according to the present invention, it is preferable that the switching unit switches the supply destination to the synchronization signal detection unit when a signal different from the transition signal is detected after switching the supply destination to the transition signal detection unit.

It is also preferable that the electronic watch according to the present invention further includes an operation control unit which, when a synchronization signal is detected, pauses the synchronization signal detection unit and activates the transition signal detection unit, and, when a transition signal is detected, pauses the transition signal detection unit and activates the control signal detection unit.

In addition, in the electronic watch according to the present invention, it is preferable that the synchronization signal detection unit and the transition signal detection unit are driven by power supplied from the photoelectric conversion unit.

In addition, in the electronic watch according to the present invention, it is preferable that the first communication method, the second communication method, and the third communication method are intensity modulation methods.

In addition, in the electronic watch according to the present invention, it is preferable that the first communication method is an intensity modulation method, and the second communication method and the third communication method are frequency modulation methods.

In the electronic watch according to the present invention, it is preferable that the first communication method is an intensity modulation method, and the second and third communication methods are phase modulation methods.

In the electronic watch according to the present invention, it is preferable that the first and second communication methods are intensity modulation methods, and the third communication method is a frequency modulation method.

In the electronic watch according to the present invention, it is preferable that the first and second communication methods are intensity modulation methods, and the third communication method is a phase modulation method.

The communication method according to the present invention is a communication method executed by an electronic watch that optically communicates with a control terminal, and is characterized in that it includes a photoelectric conversion unit that receives an optical signal from the control terminal and converts it into an electrical signal, accepts a synchronization signal according to a first communication method transmitted from the control terminal via the photoelectric conversion unit, and when the synchronization signal is detected, accepts a transition signal according to a second communication method transmitted from the control terminal via the photoelectric conversion unit, and when the transition signal is detected, accepts a control signal according to a third communication method transmitted from the control terminal via the photoelectric conversion unit, and when the control signal is detected, controls the electronic watch based on the control signal.

The electronic watch and communication method of the present invention reduce power consumption while reducing the operational burden on the user for detecting optical signals.

FIG. 1 is a diagram illustrating an example of a schematic configuration of a communication system 10. FIG. FIG. 2 is a cross-sectional view of the electronic timepiece 1. FIG. 1 is a diagram showing an example of a schematic configuration of an electronic timepiece 1. 4 is a schematic diagram for explaining a synchronization signal and a transition signal; FIG. FIG. 2 is a diagram illustrating an example of a schematic configuration of a control terminal 2. FIG. 2 is a state transition diagram of the electronic watch 1. FIG. 11 is a sequence diagram showing an example of a flow of a communication process. FIG. 2 is a schematic diagram for explaining the power consumption of the electronic timepiece 1. FIG. 1 is a diagram showing an example of a schematic configuration of an electronic timepiece 1a. FIG. 4 is a schematic diagram for explaining the power consumption of the electronic timepiece 1a. FIG. 2 is a diagram showing an example of a schematic configuration of an electronic timepiece 1b. FIG. 4 is a state transition diagram of the electronic timepiece 1b. FIG. 11 is a sequence diagram showing an example of the flow of a second communication process. 10 is a schematic diagram for explaining power consumption of the electronic timepiece 1b. FIG.

Various embodiments of the present invention will be described below with reference to the drawings. Please note that the technical scope of the present invention is not limited to these embodiments, but extends to the inventions described in the claims and their equivalents.

Fig. 1 is a diagram showing an example of the schematic configuration of a communication system 10 according to the present invention. The communication system 10 has an electronic watch 1 and a control terminal 2. The electronic watch 1 is a watch that performs optical communication with the control terminal 2, for example a wristwatch equipped with a solar cell. The control terminal 2 is an information processing terminal having a light-emitting unit that can blink, such as a smartphone, mobile phone, or tablet PC (Personal Computer). The light-emitting unit is, for example, an LED (Light Emitting Diode) light source used as a flash for a camera equipped in the control terminal 2, but is not limited to this and may be a backlight for a liquid crystal display, etc.

The control terminal 2 controls the light emitting unit to irradiate the electronic watch 1 with a light signal whose intensity changes according to a predetermined pattern. The electronic watch 1 controls the electronic watch 1 based on the control signal contained in the light signal. Examples of control of the electronic watch 1 include setting the time, changing the time zone, and setting an alarm.

Figure 2 is a front view of the electronic watch 1, and Figure 3 is a cross-sectional view of the electronic watch 1. Figure 3 is a cross-sectional view taken along line III-III in Figure 2.

The electronic watch 1 has an exterior case 11, a crystal 12, a dial 13, an hour hand 141, a minute hand 142, a second hand 143, a crown 16, a solar cell 17, etc. The solar cell 17 is an example of a photoelectric conversion unit. The electronic watch 1 may also have a photodiode or the like as an example of a photoelectric conversion unit.

The exterior case 11 is a flat member that houses the dial 13 and other components. The exterior case 11 is formed from an annular bezel 111 provided on the front of the electronic watch 1, a back cover 113 provided on the back, and a case 112 that joins the bezel 111 and the back cover 113.

The bezel 111 is attached to the front of the case 112 by adhesive member 114. The case 112 is attached to the back cover 113 at its rear by adhesive member 115. The case 112 also has an attachment portion 118 formed on its outer periphery for attaching a band. The case 112 also has a crown hole formed on its outer periphery for inserting the crown 16.

The bezel 111, case 112, and back cover 113 are made of stainless steel. The bezel 111, case 112, and back cover 113 may also be made of other metals such as titanium or gold, or resin, etc.

The crystal 12 is attached to the front of the exterior case 11 so as to be surrounded by the bezel 111. The crystal 12 is a transparent glass plate formed into a disk shape, and is made of sapphire glass, mineral glass, or the like. The crystal 12 is adhered to the front of the case 112 with an adhesive member 124, and covers the dial 13, hour hand 141, minute hand 142, and second hand 143, protecting them while making them visible from the front.

The dial 13 is a flat member with the hour characters 131 indicated by the hour hand 141, minute hand 142, and second hand 143 displayed on the front. The dial 13 is built into the exterior case 11 parallel to the crystal 12. The dial 13 has a through hole 137 in the center that passes through the front and back of the dial 13, and the rotation axes of the hour hand 141, minute hand 142, and second hand 143 are inserted into the through hole 137. A first endpaper 116 having a circular ring shape is arranged to cover the outer periphery of the front of the dial 13. A second endpaper 117 is arranged to cover the outer periphery of the first endpaper 116 and the inner periphery of the body 112 of the exterior case 11.

The hour hand 141, minute hand 142, and second hand 143 are provided on the front side of the dial 13, and are driven by the movement 14 housed in the housing section 15 on the back side of the dial 13 to point to the hour character 131 displayed on the dial 13. The rotation shafts of the hour hand 141, minute hand 142, and second hand 143 are inserted through the coaxial hour hand pipe 144, minute hand pipe 145, and second hand pipe 146, respectively, and connected to the movement 14. The hour hand 141, minute hand 142, and second hand 143 are driven by the transmission of rotational force from the movement 14, which will be described later, via the rotation shaft. In FIG. 3, the configuration of the movement 14 housed in the housing section 15 is omitted.

The crown 16 is a rotatable shaft-shaped member that is inserted into a crown hole provided in the body 112 of the exterior case 11 and connected to the movement 14. The rotational force of the crown 16 is transmitted to the hour hand 141, minute hand 142, and second hand 143 via the movement 14 to set the time, causing the hour hand 141, minute hand 142, and second hand 143 to rotate.

The solar cell 17 is a component that receives optical signals from the control terminal 2 and converts them into electrical signals. The solar cell 17 is made of amorphous silicon or polycrystalline silicon and is formed in a roughly flat plate shape, and is provided behind the dial 13 so as to face the dial 13. The solar cell 17 generates a current according to the intensity of the incident light that is incident on the electronic timepiece 1 and transmitted through the dial 13, by the photoelectric effect. The solar cell 17 may also be provided in a ring shape along the outer periphery of the dial 13.

Figure 4 is a diagram showing an example of the schematic configuration of the electronic watch 1. The electronic watch 1 further includes a secondary battery 151, a memory unit 152, an audio output unit 153, a switching unit 18, a detection unit 180, and a processing unit 19. Each of these components is housed in the housing unit 15.

The secondary battery 151 is a component for supplying power to each component of the electronic watch 1, and is, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery. The secondary battery 151 is charged by a current generated by the solar cell 17 according to the intensity of incident light. The secondary battery 151 and the solar cell 17 are connected via a power switching unit 171 that can switch between opening and closing an electrical circuit. The opening and closing of the electrical circuit is switched according to the voltage of the secondary battery 151, or according to the state of communication between the electronic watch 1 and the control terminal 2, which will be described later. This prevents overcharging of the secondary battery 151, and ensures that signals necessary for communication between the electronic watch 1 and the control terminal 2 are appropriately supplied to each unit.

As described above, the movement 14 is configured to drive the hour hand 141, minute hand 142, and second hand 143. The movement 14 is a quartz movement having a gear train consisting of a crystal oscillator, a control circuit, a stepping motor, and multiple gears. The crystal oscillator generates a voltage signal of a predetermined frequency by the piezoelectric effect. The control circuit functions as a frequency divider circuit, and outputs a pulse signal of a predetermined period by converting the frequency of the voltage signal generated by the crystal oscillator. The stepping motor rotates the rotor a predetermined angle at a predetermined period in response to the pulse signal output by the control circuit. The gear train drives the hour hand 141, minute hand 142, and second hand 143 by transmitting the rotational force of the rotor to each of the hour hand 141, minute hand 142, and second hand 143 while changing the number of rotations.

The control circuit also outputs a pulse signal based on a drive control signal from the processing unit 19 to rotate the rotor of the stepping motor. The control circuit also monitors the pulse signal output to the stepping motor to obtain the indicated time indicated by the hour hand 141, minute hand 142, and second hand 143, and supplies this to the processing unit 19.

The memory unit 152 is configured to store data and programs, and includes, for example, a semiconductor memory. The memory unit 152 stores operating system programs, driver programs, application programs, data, etc., used in processing by the processing unit 19.

The audio output unit 153 is configured to output audio, and includes, for example, a speaker. The audio output unit 153 outputs audio based on an audio signal from the processing unit 19. The audio output unit 153 outputs an alarm audio based on, for example, an audio signal supplied at each alarm time.

The switching unit 18 is configured to switch the supply destination of the electrical signal converted from the optical signal by the solar cell, and includes a first switch 18a, a second switch 18b, and a third switch 18c. The first switch 18a, the second switch 18b, and the third switch 18c are members that respectively switch between opening and closing the electrical paths between the solar cell 17 and the synchronization signal detection unit 182, the transition signal detection unit 183, and the control signal detection unit 184. The first switch 18a, the second switch 18b, and the third switch 18c switch between opening and closing the electrical paths based on a switching control signal from the detection unit 180, thereby switching the supply destination of the electrical signal.

The detection unit 180 is configured to detect the optical signal transmitted from the control terminal 2, and includes an operation control unit 181, a synchronization signal detection unit 182, a transition signal detection unit 183, and a control signal detection unit 184.

The operation control unit 181 is an electronic circuit that controls the operation of the switching unit 18, the synchronization signal detection unit 182, the transition signal detection unit 183, and the control signal detection unit 184. The operation of the operation control unit 181 will be described later with reference to FIG. 7.

The synchronization signal detection unit 182 is configured to detect a synchronization signal conforming to the first communication method transmitted from the control terminal 2, and has a sampling circuit and a detection and judgment circuit. The sampling circuit samples the electrical signal converted from the optical signal by the solar cell 17 at a predetermined sampling period. If the sampled electrical signal matches a pattern corresponding to the synchronization signal, the detection and judgment circuit judges that the synchronization signal has been detected, and supplies the judgment result to the operation control unit 181.

Figure 5(a) is a schematic diagram for explaining the synchronization signal included in the optical signal. The synchronization signal is a time series signal in which multiple symbols, each lasting for the first symbol time Tsy1, are transmitted sequentially according to time t. Each symbol is either a symbol with high light intensity I (hereinafter referred to as "H") or a symbol with low light intensity I (hereinafter referred to as "L"). In the example shown in Figure 5(a), the synchronization signal consists of three symbols, HLH, each lasting for the first symbol time Tsy1.

Figure 5(b) is a schematic diagram for explaining the sampled synchronization signal. The sampling circuit samples the electrical signal converted from the optical signal, for example, at a first sampling period Tsm1 that is less than half the first symbol time Tsy1. The detection and determination circuit determines that the synchronization signal has been detected when the sampled electrical signal matches the HLH pattern of the synchronization signal.

For example, if the voltage value of the sampled electrical signal is greater than or equal to the first threshold th1 twice in a row, the detection and judgment circuit determines that an H symbol has been transmitted. If the voltage value is less than a second threshold th2, which is smaller than the first threshold th1, twice in a row, the detection and judgment circuit determines that an L symbol has been transmitted. After repeating this type of judgment and determining that three symbols, HLH, have been transmitted, the detection and judgment circuit determines that a synchronization signal has been detected.

The first symbol time Tsy1 is, for example, 1 second. That is, the communication speed of the first communication method is 1 symbol per second. In this case, the sampling period Tsm1 of the sampling circuit is set to, for example, 0.5 seconds. Furthermore, the values of the first threshold th1 and the second threshold th2 are determined based on the illuminance of the light received by the solar cell 17. For example, the first threshold th1 is a voltage value when the illuminance is 10,000 lux, and the second threshold th2 is a voltage value when the illuminance is 500 lux.

The symbol determination may be based only on the first threshold th1. In this case, the detection and determination circuit determines that an H symbol has been transmitted if the voltage value of the sampled electrical signal is equal to or greater than the first threshold th1, and determines that an L symbol has been transmitted if the voltage value is less than the first threshold th1. In this case, the first threshold th1 is, for example, the voltage value when the illuminance of the light received by the solar cell 17 is 5000 lux. The threshold settings and symbol determination criteria are not limited to the above example, and may be set as appropriate.

Returning to FIG. 4, the transition signal detection unit 183 is configured to detect a transition signal conforming to the second communication method transmitted from the control terminal 2, and has a sampling circuit and a detection judgment circuit. The sampling circuit and detection judgment circuit judge whether or not a transition signal has been detected in the same manner as when the sampling circuit and detection judgment circuit of the synchronization signal detection unit 182 detect a synchronization signal, and supply the judgment result to the operation control unit 181.

Figure 5(c) is a schematic diagram for explaining the transition signal contained in the optical signal, and Figure 5(d) is a schematic diagram for explaining the sampled transition signal. The transition signal is a time-series signal consisting of multiple symbols, each of which lasts for a second symbol time Tsy2 that is shorter than the first symbol time Tsy1. The number of symbols in the transition signal is greater than the number of symbols in the synchronization signal. In the example shown in Figure 5(c), the transition signal consists of six symbols, HLHLLH, each of which lasts for the second symbol time Tsy2.

The second symbol time Tsy2 is, for example, 0.5 seconds. In other words, the communication speed of the second communication method is 2 symbols per second. In this case, the sampling period Tsm2 of the sampling circuit is set to, for example, 0.25 seconds.

Returning to FIG. 4, the control signal detection unit 184 is configured to detect a control signal conforming to the third communication method transmitted from the control terminal 2, and has a sampling circuit and a demodulation circuit. The sampling circuit samples the electrical signal converted from the optical signal by the solar cell 17 at a predetermined sampling period. The demodulation circuit demodulates the control signal based on the pattern of the sampled electrical signal and converts it into control data. The demodulation circuit supplies the control data to the processing unit 19.

The symbol time of the control signal is, for example, 0.01 seconds or less. In other words, the communication speed of the third communication method is, for example, 100 symbols per second or more.

The synchronization signal detection unit 182, the transition signal detection unit 183, and the control signal detection unit 184 start or pause based on a control signal from the operation control unit 181. Pausing refers to reducing power consumption in the circuit by, for example, cutting off the power supply to part or all of the circuit (going to sleep).

The processing unit 19 is configured to comprehensively control the operation of the electronic watch 1, and includes one or more processors and their peripheral circuits. The processing unit 19 includes, for example, a CPU (Central Processing Unit), an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), etc. The processing unit 19 controls the operation of each component of the electronic watch 1 or executes processing based on the programs stored in the memory unit 152.

The processing unit 19 has an acquisition unit 191 and a control unit 192 as its functional blocks. Each of these units is a functional module realized by a program executed by the processing unit 19. Each of these units may be implemented in the electronic watch 1 as firmware.

Figure 6 is a diagram showing an example of a schematic configuration of the control terminal 2. The control terminal 2 has a terminal storage unit 21, an operation unit 22, a light-emitting unit 23, and a terminal processing unit 24.

The device storage unit 21 is configured to store data and programs, and includes, for example, a semiconductor memory. The device storage unit 21 stores operating system programs, driver programs, application programs, data, etc., used for processing by the device processing unit 24.

The operation unit 22 is configured to receive input operations for the control terminal 2, and includes, for example, a touch panel. The operation unit 22 may include a keypad, a keyboard, a mouse, or the like. The operation unit 22 receives input operations by a user, and supplies an input signal corresponding to the received input operation to the terminal processing unit 24.

The light-emitting unit 23 is configured to emit an optical signal, and includes, for example, an LED light source. The light-emitting unit 23 blinks based on a light-emitting control signal supplied from the device processing unit 24. The light-emitting unit 23 can also emit light of any desired brightness by performing PWM (Pulse Width Modulation) control or the like based on the light-emitting control signal.

The device processing unit 24 is configured to comprehensively control the operation of the control terminal 2, and includes one or more processors and their peripheral circuits. The device processing unit 24 includes, for example, a CPU, an LSI, an ASIC, a DSP, etc. The device processing unit 24 controls the operation of each component of the control terminal 2 or executes processing based on the programs stored in the terminal storage unit 21.

The device processing unit 24 has a reception unit 241 and a light emission control unit 242 as its functional blocks. Each of these units is a functional module realized by a program executed by the device processing unit 24. Each of these units may be implemented in the control terminal 2 as firmware.

Figure 7 is a state transition diagram of the electronic watch 1. The electronic watch 1 is in a synchronization waiting state S1 until it detects a synchronization signal. In the synchronization waiting state S1, the electronic watch 1 accepts a synchronization signal. In the synchronization waiting state S1, the transition signal detection unit 183 and the control signal detection unit 184 are inactive.

When a synchronization signal is detected in the synchronization waiting state S1, the synchronization signal detection unit 182 supplies the operation control unit 181 with a determination result indicating that a synchronization signal has been detected. Based on the determination result, the operation control unit 181 pauses the synchronization signal detection unit 182 and starts the transition signal detection unit 183. The operation control unit 181 also supplies a switching control signal to the switching unit 18, and switches the supply destination of the electrical signal from the solar cell 17 from the synchronization signal detection unit 182 to the transition signal detection unit 183. This causes the electronic watch 1 to transition waiting state S2 (T12) and accepts the transition signal.

When a transition signal is detected in the transition waiting state S2, the transition signal detection unit 183 supplies the operation control unit 181 with a determination result indicating that a transition signal has been detected. Based on the determination result, the operation control unit 181 pauses the transition signal detection unit 183 and starts the control signal detection unit 184. The operation control unit 181 also supplies a switching control signal to the switching unit 18, switching the destination of the electrical signal from the solar cell 17 from the transition signal detection unit 183 to the control signal detection unit 184. This causes the electronic watch 1 to transition to the control waiting state S3 (T23) and accepts the control signal.

If a transition signal is not detected until the first time has elapsed since transition to the transition waiting state S2, the operation control unit 181 pauses the transition signal detection unit 183 and activates the synchronization signal detection unit 182. The operation control unit 181 also supplies a switching control signal to the switching unit 18 to switch the supply destination of the electrical signal from the transition signal detection unit 183 to the synchronization signal detection unit 182. This causes the electronic watch 1 to transition to the synchronization waiting state S1 (T21). Note that a case in which a transition signal is not detected before the first time has elapsed refers to, for example, a case in which the first symbol of the multiple symbols constituting the transition signal is not detected before the first time has elapsed. In other words, the first time is the waiting time from transition to the transition waiting state S2 until the first symbol of the transition signal is received. The first time is, for example, 2 seconds.

When a control signal is detected in the control waiting state S3, the control signal detection unit 184 supplies control data to the processing unit 19. As a result, the processing unit 19 controls the electronic watch 1 based on the control signal. The electronic watch 1 also transitions again to the control waiting state S3 (T33).

If no control signal is detected before the second time has elapsed since transitioning to the control waiting state S3, the operation control unit 181 pauses the control signal detection unit 184 and activates the synchronization signal detection unit 182. The operation control unit 181 also supplies a switching control signal to the switching unit 18, switching the supply destination of the electrical signal from the control signal detection unit 184 to the synchronization signal detection unit 182. This causes the electronic watch 1 to transition to the synchronization waiting state S1 (T31). Note that if a control signal is not detected before the second time has elapsed, this refers to, for example, if the first symbol of the multiple symbols that make up the control signal has not been detected before the second time has elapsed. In other words, the second time is the waiting time from transitioning to the control waiting state S3 until the first symbol of the control signal is received. The second time is, for example, 5 seconds.

Figure 8 is a sequence diagram showing an example of the flow of communication processing executed by the communication system 10. The communication processing is realized by the processing unit 19, which executes a program, and the terminal processing unit 24, working together with each component of the electronic watch 1 and the control terminal 2. When the communication processing starts, the electronic watch 1 is in a synchronization waiting state S1, and the synchronization signal detection unit 182 is accepting a synchronization signal.

First, the reception unit 241 of the control terminal 2 receives a control instruction from the user (S101). The reception unit 241 receives the control instruction by receiving an operation by the user on the operation unit 22. The control instruction is an instruction for controlling the electronic clock 1, and will be described below as an instruction to set the time.

Next, the light emission control unit 242 transmits a synchronization signal (S102). The light emission control unit 242 transmits an optical signal including the synchronization signal to the electronic watch 1 by blinking the light emission unit 23 in a pattern corresponding to the synchronization signal.

Then, the synchronization signal detection unit 182 of the electronic watch 1 detects a synchronization signal (S103). If a synchronization signal is detected, the electronic watch 1 transitions to a transition waiting state S2, and the transition signal detection unit 183 accepts the transition signal.

Then, the light emission control unit 242 of the control terminal 2 transmits a transition signal (S104). The light emission control unit 242 transmits an optical signal including the transition signal to the electronic watch 1 by blinking the light emission unit 23 in a preset pattern corresponding to the transition signal.

Then, the transition signal detection unit 183 of the electronic watch 1 detects a transition signal (S105). If a transition signal is detected, the electronic watch 1 transitions to a control waiting state S3, and the control signal detection unit 184 accepts a control signal.

Next, the light emission control unit 242 of the control terminal 2 transmits a control signal (S106). The light emission control unit 242 acquires control data corresponding to the control instruction input in S101 from the terminal storage unit 21. The light emission control unit 242 transmits an optical signal including a control signal to the electronic watch 1 by blinking the light emission unit 23 in a pattern corresponding to the control data. If the control instruction is an instruction to set the time, the control data includes information instructing the time to be set and information indicating a target time for setting the time.

Then, the control signal detection unit 184 of the electronic watch 1 detects a control signal (S107). When a control signal is detected, the control signal detection unit 184 supplies control data corresponding to the control signal to the processing unit 19. The acquisition unit 191 acquires the supplied control data.

The control unit 192 controls the electronic watch 1 based on the acquired control data (S108), and the communication process ends. The control unit 192 acquires the target time for time adjustment contained in the control data. The control unit 192 acquires the current indicated time from the control circuit of the movement 14. The control unit 192 adjusts the time by supplying to the movement 14 a drive control signal that rotates the stepping motor a number of times equivalent to the difference between the target time and the indicated time.

As described above, the electronic watch 1 accepts a synchronization signal, accepts a transition signal when the synchronization signal is detected, accepts a control signal when the transition signal is detected, and controls the electronic watch 1 when the control signal is detected. This allows the electronic watch 1 to reduce the operational burden on the user for detecting optical signals while suppressing power consumption.

9(a) is a schematic diagram for explaining the change over time in power consumption when the electronic watch 1 communicates. In FIG. 9(a), the power consumption P of the electronic watch 1 is shown as the power consumption P1 of the synchronization signal detection unit 182, the transition signal detection unit 183, and the control signal detection unit 184, and the power consumption P2 of the processing unit 19, and the same applies to the following. When the electronic watch 1 communicates, the electronic watch 1 transitions to a synchronization waiting state S1, a transition waiting state S2, and a control waiting state S3 in sequence, and communicates with the control terminal 2 in the control waiting state S3. Since the power consumption of the synchronization signal detection unit 182, the transition signal detection unit 183, and the control signal detection unit 184 increases in this order, as shown in FIG. 9(a), the power consumption P1 increases as the electronic watch 1 transitions to the synchronization waiting state S1, the transition waiting state S2, and the control waiting state S3. In addition, since the acquisition unit 191 and the control unit 192 operate in the control waiting state S3, the power consumption P2 of the processing unit 19 also occurs.

Figure 9 (b) is a schematic diagram for explaining the change in power consumption over time when the electronic watch 1 is not communicating. Because the synchronization signal is a signal with a relatively low communication speed, changes in the amount of light received that accompany daily use of the electronic watch 1, such as when the user of the electronic watch 1 moves from the shade to the sun, may be erroneously detected as a synchronization signal. Therefore, as shown in Figure 9 (b), even if the electronic watch 1 is not communicating, the electronic watch 1 may transition to the transition waiting state S2.

On the other hand, because the transition signal is a signal with a communication speed greater than that of the synchronization signal, there is little possibility that a change in the amount of light received due to daily use of the electronic watch 1 will be erroneously detected as a transition signal. Therefore, even if the electronic watch 1 transitions to the transition waiting state S2, if a transition signal is not detected before the first time has elapsed, the electronic watch 1 will transition back to the synchronization waiting state S1, and the electronic watch 1 will not transition to the control waiting state S3. As a result, even if the electronic watch 1 erroneously detects the synchronization signal, the power consumption P1 is kept small as shown in Figure 9 (b), and power consumption P2 of the processing unit 19 is not generated, so the power consumption of the electronic watch 1 is reduced.

The electronic watch 1 may transition to the synchronization waiting state S1 when a signal different from the transition signal is detected after transition to the transition waiting state S2. In this case, the transition signal detection unit 183 sequentially judges symbols based on the sampled electrical signal. When the transition signal detection unit 183 judges the same number of symbols as the symbols included in the transition signal, it judges whether the symbol judgment result matches the transition signal pattern. If it is judged that the judgment result matches the transition signal pattern, the operation control unit 181 controls the switching unit 18 to switch the supply destination of the electrical signal to the control signal detection unit 184, and transitions the electronic watch 1 to the control waiting state S3. If it is judged that the judgment result does not match the transition signal pattern, the operation control unit 181 controls the switching unit 18 to switch the supply destination of the electrical signal to the synchronization signal detection unit 182, and transitions the electronic watch 1 to the synchronization waiting state S1. As a result, when the synchronization signal is erroneously detected, the time from transition to the transition waiting state S2 to transition to the synchronization waiting state S1 is shortened, and power consumption is reduced.

The transition signal detection unit 183 may also sequentially determine whether or not the received symbol matches the pattern of the transition signal each time it receives a symbol included in the transition signal. In this case, when it is determined that the received symbol pattern does not match the pattern of the transition signal, the operation control unit 181 controls the switching unit 18 to switch the supply destination of the electrical signal to the synchronization signal detection unit 182, and transitions the electronic watch 1 to the synchronization waiting state S1. In this way, it becomes possible to switch the supply destination of the electrical signal to the synchronization signal detection unit 182 due to a false detection of the synchronization signal before receiving the same number of symbols as the symbols included in the transition signal, further reducing power consumption.

In the above description, the control instruction is an instruction to set the time, but this is not a limited example. For example, the control instruction may be an instruction to change the time zone. In this case, the control data includes information on the new time zone. Then, in S108 of the communication process, the control unit 192 acquires information on the current time zone from the storage unit 152. The control unit 192 adjusts the command time to the time in the new time zone by supplying to the movement 14 a drive control signal that rotates the stepping motor a number of times corresponding to the time difference between the new time zone and the current time zone. The control unit 192 also stores the information on the new time zone in the storage unit 152 as information on the current time zone.

The control instruction may be to set an alarm. In this case, the control data includes information on the alarm time. Then, in S108 of the communication process, the control unit 192 stores the information on the alarm time in the memory unit 152. The control unit 192 periodically obtains the designated time from the movement 14, and when the designated time matches the alarm time, it supplies audio data to the audio output unit 153 to output an alarm sound.

In the above description, the electronic watch 1 has a switching unit 18, but this is not limited to the example, and the electronic watch 1 does not need to have a switching unit 18. In this case, the electrical signal from the solar cell 17 is supplied to the synchronization signal detection unit 182, the transition signal detection unit 183, and the control signal detection unit 184, respectively.

In the above description, the electronic watch 1 has an operation control unit 181, but it does not have to have an operation control unit 181. In this case, the synchronization signal detection unit 182, transition signal detection unit 183, and control signal detection unit 184 will not pause, but when the electronic watch 1 is not communicating, no power is consumed by the processing unit 19, so the power consumption of the electronic watch 1 can be reduced.

In the above description, the communication speed of the first communication method is 1 symbol per second, and the communication speed of the second communication method is 2 symbols per second, but this is not limited to this example, and these speeds may be set arbitrarily as long as the communication speed of the second communication method is greater than the communication speed of the first communication method. The number of symbols of the synchronization signal and transition signal may also be set arbitrarily. However, since a large number of symbols in a signal will require a long time for detection, it is preferable to set these parameters so that the signal length (the time the signal continues, which is the value obtained by dividing the number of symbols in the signal by the communication speed) of the synchronization signal and transition signal is within 5 seconds.

In the above description, the synchronization signal, transition signal, and control signal are so-called binary modulation signals in which each symbol takes either H or L, but this is not limited to the example. These signals may also be so-called multi-value modulation signals in which each symbol takes either of three or more types of symbols. For example, in the electronic watch 1, the synchronization signal and transition signal may be binary modulation signals, and the control signal may be a multi-value modulation signal. This enables the electronic watch 1 to communicate control data efficiently.

The first, second and third communication methods are all intensity modulation methods that vary the light intensity for each symbol, but are not limited to this example. These signals may be frequency modulation methods that vary the light intensity at a predetermined modulation frequency and vary the modulation frequency for each symbol. In this case, the synchronization signal detection unit 182, the transition signal detection unit 183 and the control signal detection unit 184 further have a digital signal processing circuit for demodulating the electrical signal sampled by the sampling circuit. The synchronization signal detection unit 182, the transition signal detection unit 183 and the control signal detection unit 184 may further have an analog detection circuit such as a quadrature detection circuit for demodulating the electrical signal, which is a frequency modulated signal, from the solar cell 17, and the signal demodulated by the analog detection circuit may be input to the sampling circuit.

These signals may be phase-modulated, changing the intensity of light at a predetermined modulation frequency and varying the phase for each symbol. In this case, the synchronization signal detector 182, the transition signal detector 183, and the control signal detector 184 further include a digital signal processing circuit for demodulating the electrical signal sampled by the sampling circuit. The synchronization signal detector 182, the transition signal detector 183, and the control signal detector 184 may further include an analog detection circuit, such as a differential detection circuit, for demodulating the electrical signal, which is a phase-modulated signal, from the solar cell 17, and may input the signal demodulated by the analog detection circuit to the sampling circuit.

At least some of the first, second, and third communication methods may employ modulation methods different from each other. For example, the first communication method may be an intensity modulation method, and the second and third communication methods may be frequency modulation methods. The first communication method may be an intensity modulation method, and the second and third communication methods may be phase modulation methods. The first and second communication methods may be intensity modulation methods, and the third communication method may be frequency modulation methods. The first and second communication methods may be intensity modulation methods, and the third communication method may be phase modulation methods.

In the above description, the electronic clock 1 has a synchronization signal detection unit 182 and a transition signal detection unit 183, but both may be implemented by a single piece of hardware. In this case, the electronic clock 1 changes the sampling period of the sampling circuit between the synchronization wait state S1 and the transition wait state S2. This makes it possible to reduce the circuit scale required by the electronic clock 1.

In the above description, the synchronization signal detection unit 182 and the transition signal detection unit 183 each have a detection judgment circuit, but this is not limited to the example. The function of the detection judgment circuit may be realized by the processing unit 19. In this way, the hardware configuration of the synchronization signal detection unit 182 and the transition signal detection unit 183 is simplified.

Figure 10 shows an example of the schematic configuration of an electronic watch 1a in which the function of the detection and judgment circuit is realized by a processing unit 19. Note that the same components as those described above are given the same reference numerals, and explanations will be omitted as appropriate. In addition to an acquisition unit 191 and a control unit 192, the processing unit 19 of the electronic watch 1a has a synchronization detection and judgment unit 193 and a transition detection and judgment unit 194 as its functional blocks.

The synchronization signal detection unit 182 and the transition signal detection unit 183 each have a sampling circuit. The sampling circuit samples the electrical signal converted from the optical signal by the solar cell 17 at a predetermined sampling period, and supplies the data of the sampled electrical signal to the processing unit 19.

When the sampled electrical signal data matches a pattern corresponding to a synchronization signal, the synchronization detection determination unit 193 determines that a synchronization signal has been detected and supplies the determination result to the operation control unit 181.

When the sampled electrical signal data matches a pattern corresponding to a transition signal, the transition detection determination unit 194 determines that a transition signal has been detected and supplies the determination result to the operation control unit 181.

11(a) is a schematic diagram for explaining the change over time in the power consumption of the electronic watch 1a when the electronic watch 1a communicates, and FIG. 11(b) is a schematic diagram for explaining the change over time in the power consumption when the electronic watch 1a does not communicate. As shown in FIGS. 11(a) and (b), in the electronic watch 1a, the power consumption P1 of the synchronization signal detection unit 182, the transition signal detection unit 183, and the control signal detection unit 184 is generated, as in the case of the electronic watch 1 described using FIG. 9. In addition, in the electronic watch 1a, the synchronization detection determination unit 193 and the transition detection determination unit 194 of the processing unit 19 operate in the synchronization waiting state S1 and the transition waiting state S2, so the power consumption P2 of the processing unit 19 is generated in these states as well. However, since the communication speed of the synchronization signal and the transition signal is not high, the power consumption P2 of the processing unit 19 in the synchronization waiting state S1 and the transition waiting state S2 is small, and the overall power consumption is suppressed.

In addition, in the electronic watch 1, only one of the functions of the detection and judgment circuit of the synchronization signal detection unit 182 and the detection and judgment circuit of the transition signal detection unit 183 may be realized by the processing unit 19.

In the above description, the synchronization signal detection unit 182 and the transition signal detection unit 183 are driven by power supplied from the secondary battery 151, but this is not limited to the example. The synchronization signal detection unit 182 and the transition signal detection unit 183 may be driven by power supplied directly from the solar cell 17.

Figure 12 is a diagram showing an example of the schematic configuration of an electronic watch 1b in which a synchronization signal detection unit 182 and a transition signal detection unit 183 are powered by a solar cell 17. As shown in Figure 12, the synchronization signal detection unit 182 and the transition signal detection unit 183 of the electronic watch 1b use the electrical signal from the solar cell 17 as a power source. The synchronization signal detection unit 182 and the transition signal detection unit 183 have a power supply circuit that smoothes the electrical signal from the solar cell 17 and adjusts the voltage, and uses the electrical signal as a power source.

Figure 13 is a state transition diagram of electronic watch 1b. Electronic watch 1b differs from electronic watch 1 in that it takes a pause state S0 in addition to a synchronization wait state S1, a transition wait state S2, and a control wait state S3. The pause state S0 is a state in which the synchronization signal detection unit 182, the transition signal detection unit 183, and the control signal detection unit 184 are all paused. The transitions between the synchronization wait state S1, the transition wait state S2, and the control wait state S3 are the same as those explained using Figure 7, so only the transitions related to the pause state S0 will be explained below.

In the synchronization waiting state S1, if the power supply from the solar cell 17 to the synchronization signal detection unit 182 is interrupted for a predetermined period of time or longer, the synchronization signal detection unit 182 goes into a pause state. This causes the electronic watch 1b to transition to a pause state S0 (T10). Similarly, in the transition waiting state S2, if the power supply from the solar cell 17 to the transition signal detection unit 183 is interrupted for a predetermined period of time or longer, the transition signal detection unit 183 goes into a pause state. At this time, the operation control unit 181 controls the switching unit 18 to switch the supply destination of the electrical signal to the synchronization signal detection unit 182. This causes the electronic watch 1b to transition to a pause state S0 (T20).

The specified time is the time from when the power supply to the synchronization signal detection unit 182 or the transition signal detection unit 183 is interrupted to when the discharge of the capacitor in the circuit of the synchronization signal detection unit 182 or the transition signal detection unit 183 is completed. The specified time is set to a time longer than the first symbol time (for example, 2 seconds). This prevents the electronic clock 1b from transitioning to the pause state S0 when the L symbol is being transmitted as the synchronization signal.

In the pause state S0, the solar cell 17 starts supplying power to the synchronization signal detection unit 182, and if this continues for a predetermined period of time or more, the synchronization signal detection unit 182 starts up. This causes the electronic watch 1b to transition to the synchronization wait state S1 (T01).

Figure 14 is a sequence diagram showing an example of the flow of the second communication process executed by a communication system having the electronic watch 1b and the control terminal 2. When the second communication process starts, the electronic watch 1b is in a pause state S0.

First, the reception unit 241 of the control terminal 2 receives a control instruction from the user (S201). Next, the light emission control unit 242 controls the light emission unit 23 to transmit a synchronization signal (S202). The synchronization signal detection unit 182 is started by power supply from the solar cell 17 that received the synchronization signal, and receives the synchronization signal (S203). This causes the electronic watch 1b to transition to a synchronization waiting state S1.

Then, the light emission control unit 242 of the control terminal 2 controls the light emission unit 23 to transmit a synchronization signal (S204). By the light emission control unit 242 continuing to transmit the synchronization signal, the synchronization signal detection unit 182 can properly detect the synchronization signal even when it takes time to start the synchronization signal detection unit 182 (for example, when the capacitor of the circuit is completely discharged). Next, the synchronization signal detection unit 182 of the electronic watch 1b detects the synchronization signal (S205). When the synchronization signal is detected, the electronic watch 1b transitions to the transition wait state S2, and the transition signal detection unit 183 accepts the transition signal.

Then, the light emission control unit 242 of the control terminal 2 controls the light emission unit 23 to transmit a transition signal (S206). The transition signal detection unit 183 of the electronic watch 1b detects the transition signal (S207). If a transition signal is detected, the electronic watch 1b transitions to a control waiting state S3, and the control signal detection unit 184 accepts a control signal.

Then, the light emission control unit 242 of the control terminal 2 controls the light emission unit 23 to transmit a control signal (S208). The control signal detection unit 184 of the electronic watch 1b detects the control signal (S209). If a control signal is detected, the acquisition unit 191 acquires control data based on the control signal, and the control unit 192 controls the electronic watch 1b based on the control data (S210).

Figure 15(a) is a schematic diagram for explaining the change over time in power consumption of electronic watch 1b when electronic watch 1b is communicating, and Figure 15(b) is a schematic diagram for explaining the change over time in power consumption when electronic watch 1b is not communicating. Note that power consumption P shown in Figures 15(a) and (b) only includes power consumption based on power supply from secondary battery 151, which affects the continuous operating time of electronic watch 1b, and does not include power consumption based on power supply from solar cell 17. In other words, power consumption P1 in Figure 15(a) only includes power consumption of control signal detection unit 184, which receives power supply from secondary battery 151.

In the electronic watch 1b, in the synchronization waiting state S1 and the transition waiting state S2, the synchronization signal detection unit 182 and the transition signal detection unit 183 are powered by the solar cell 17, not the secondary battery 151. Therefore, as shown in Figures 15(a) and (b), in the electronic watch 1b, power consumption P1 based on power supply from the secondary battery 151 does not occur in the synchronization waiting state S1 and the transition waiting state S2, but occurs only when the control signal detection unit 184 is activated in the control waiting state S3. Also, as in the case of the electronic watch 1 shown in Figure 9, power consumption P2 of the processing unit 19 occurs only in the control waiting state S3. As a result, when communication is not performed, power consumption P1 and P2 based on power supply from the secondary battery 151 does not occur, making it possible for the electronic watch 1b to significantly reduce power consumption.

In addition, in the electronic watch 1b, only one of the synchronization signal detection unit 182 and the transition signal detection unit 183 may be powered by the solar cell 17, and the other may be powered by the secondary battery 151. Even in this way, the electronic watch 1b can reduce power consumption when no communication is taking place. Also, the switching unit 18 may be powered by the solar cell 17.

Those skilled in the art should understand that various changes, substitutions, and modifications can be made to the present invention without departing from the spirit and scope of the present invention. For example, the processing of each part described above may be performed in a different order as appropriate within the scope of the present invention. Furthermore, the above-described embodiments and modifications may be implemented in combination as appropriate within the scope of the present invention.

REFERENCE SIGNS LIST 1 Electronic clock 17 Solar cell 18 Switching unit 181 Operation control unit 182 Synchronization signal detection unit 183 Transition signal detection unit 184 Control signal detection unit 191 Acquisition unit 192 Control unit

Claims (14)

An electronic watch that optically communicates with a control terminal,
an opto-electrical converter that receives an optical signal from the control terminal and converts it into an electrical signal;
a synchronization signal detection unit that receives a synchronization signal conforming to a first communication method transmitted from the control terminal via the photoelectric conversion unit;
a transition signal detection unit that receives a transition signal conforming to a second communication method transmitted from the control terminal via the photoelectric conversion unit when the synchronization signal is detected;
a control signal detection unit that receives a control signal according to a third communication method transmitted from the control terminal via the photoelectric conversion unit when the transition signal is detected;
a control unit that controls the electronic timepiece based on the control signal when the control signal is detected ,
an operation control unit that, when the transition signal is not detected after the synchronization signal is detected, does not start the control signal detection unit, but starts the synchronization signal detection unit to receive the synchronization signal;
An electronic watch characterized by: An electronic watch that optically communicates with a control terminal,
an opto-electrical converter that receives an optical signal from the control terminal and converts it into an electrical signal;
a synchronization signal detection unit that receives a synchronization signal conforming to a first communication method transmitted from the control terminal via the photoelectric conversion unit;
a transition signal detection unit that receives a transition signal conforming to a second communication method transmitted from the control terminal via the photoelectric conversion unit when the synchronization signal is detected;
a control signal detection unit that receives a control signal according to a third communication method transmitted from the control terminal via the photoelectric conversion unit when the transition signal is detected;
a control unit that controls the electronic timepiece based on the control signal when the control signal is detected,
The first communication method is communicated at a lower communication speed than the second communication method,
The second communication method is communicated at a lower communication speed than the third communication method.
An electronic watch characterized by : a switching unit that switches a supply destination of the converted electrical signal from the synchronization signal detection unit to the transition signal detection unit when the synchronization signal is detected, and that switches the supply destination from the transition signal detection unit to the control signal detection unit when the transition signal is detected.
3. The electronic watch according to claim 1 or 2 . the switching unit switches the supply destination to the synchronization signal detection unit when the transition signal is not detected until a first time has elapsed since the supply destination was switched to the transition signal detection unit;
4. The electronic watch according to claim 3 . the switching unit switches the supply destination to the synchronization signal detection unit when a signal different from the transition signal is detected after the supply destination is switched to the transition signal detection unit;
4. The electronic watch according to claim 3 . an operation control unit that, when the synchronization signal is detected, pauses the synchronization signal detection unit and starts the transition signal detection unit, and, when the transition signal is detected, pauses the transition signal detection unit and starts the control signal detection unit;
3. The electronic watch according to claim 2 . the synchronization signal detection unit and the transition signal detection unit are driven by power supplied from the photoelectric conversion unit.
An electronic watch according to any one of claims 1 to 6 . the first communication method, the second communication method, and the third communication method are intensity modulation methods.
An electronic watch according to any one of claims 1 to 7 . the first communication method is an intensity modulation method,
The second communication method and the third communication method are frequency modulation methods.
An electronic watch according to any one of claims 1 to 7 . the first communication method is an intensity modulation method,
The second communication method and the third communication method are phase modulation methods.
An electronic watch according to any one of claims 1 to 7 . the first communication method and the second communication method are intensity modulation methods,
The third communication method is a frequency modulation method.
An electronic watch according to any one of claims 1 to 7 . the first communication method and the second communication method are intensity modulation methods,
The third communication method is a phase modulation method.
An electronic watch according to any one of claims 1 to 7. A communication method for an electronic watch that performs optical communication with a control terminal, comprising the steps of:
an optical/electrical converter receives an optical signal from the control terminal and converts it into an electrical signal;
receiving a synchronization signal conforming to a first communication method transmitted from the control terminal via the photoelectric conversion unit;
receiving a transition signal conforming to a second communication method transmitted from the control terminal via the photoelectric conversion unit when the synchronization signal is detected;
when the transition signal is detected, receiving a control signal conforming to a third communication method transmitted from the control terminal via the photoelectric conversion unit;
When the control signal is detected, the electronic timepiece is controlled based on the control signal.
when the transition signal is not detected after the synchronization signal is detected, a control signal detection unit that receives the control signal is not started, and a synchronization signal detection unit that receives the synchronization signal is started to receive the synchronization signal.
A communication method comprising: A communication method for an electronic watch that performs optical communication with a control terminal, comprising the steps of:
an optical/electrical converter receives an optical signal from the control terminal and converts it into an electrical signal;
receiving a synchronization signal conforming to a first communication method transmitted from the control terminal via the photoelectric conversion unit;
receiving a transition signal conforming to a second communication method transmitted from the control terminal via the photoelectric conversion unit when the synchronization signal is detected;
when the transition signal is detected, receiving a control signal conforming to a third communication method transmitted from the control terminal via the photoelectric conversion unit;
When the control signal is detected, the electronic timepiece is controlled based on the control signal.
The first communication method is communicated at a communication speed lower than that of the second communication method,
The second communication method is communicated at a lower communication speed than the third communication method.
A communication method comprising:

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